Chain saws are well known means for cutting wood and the like and used properly can greatly reduce work, however, if not used carefully user injury can occur. As a result, safety features are desirable. Critical to optimum operation is the capability of a chain saw system to maintain proper tension on a cutter blade containing chain, and critical to safety is the ability to stop a cutter blade containing chain from moving when the motor is running but the chain saw is not being applied to useful work. That is, efficient chain saw chain tensioning and braking systems provide utility. Further, it must be understood that chain saws are very low torque but high speed systems that derive cutting ability by generating high chain speed. That is, at a given torque, the cutting power is directly proportional to chain speed. It is therefore common for a chain saw to stall in use due to minor chain pinching, taking too big a “bite” of, or causing too much down force on, an item being cut. Further, chain pinching and the like is more likely when chain tension is not proper, and it is noted, too high a tension in a chain saw chain can cause a chain motion stopping, (ie. braking), result.
In light of the foregoing it is generally disclosed at this point that the present invention is an assisted braking system and method for application to chain saw chains.
With an eye to the present invention a Search of patents was performed.
U.S. Pat. No. 5,528,835 to Ra is identified because it describes a chain saw chain tensioning system.
U.S. Pat. No. 5,174,029 to Talberg is identified as it describes a chain saw chain tensioning system.
U.S. Pat. Nos. 5,491,899 and 5,522,143 to Schliemann et al. describe saw chain tensioning systems; and U.S. Pat. No. 4,594,780 to Schliemann et al. describe chain saw chain motion braking systems.
U.S. Pat. No. 5,233,750 to Wolf et al. is identified as describing a chain saw chain braking system.
U.S. Pat. No. 5,101,567 to Cool is identified and describes a braking mechanism (40) and brake lever (42).
U.S. Pat. No. 3,793,727 to Moore describes a system in which two handles must be engaged against the chain saw frame to allow the chain to move. If either is released the chain stops.
U.S. Pat. Nos. 4,924,577 to Leini and 4,611,401 to Piller are included to show that the Chain Guide can be split in a way that allows extending the length thereof by adding sections.
U.S. Pat. No. 5,445,365 to Forderer shows application of a “dumbbell” element, but it's applied as a connection element, rather than a means to line-up ends of a Slit Chain Saw Chain Guide.
Patents identified and which are of general interest are U.S. Pat. Nos. 5,249,362 to Harding and 4,382,334 to Reynolds.
Patents which mention magnetic material somehow applied in a chain saw, and were cited by the Examiner Prosecution of a Parent Application are:                Fukushima U.S. Pat. No. 4,060,985;        VanHalderen U.S. Pat. No. 4,373,265;        Bass U.S. Pat. No. 4,534,112;        Raiski U.S. Pat. No. 4,677,746;        Dooley U.S. Pat. No. 3,857,180;        Wilkin U.S. Pat. No. 3,485,326.No patent or combination of patents, however is believed to obviate a chain saw which comprises a clutch plate comprising at least one channel having functionally slidably present therewithin a wedge element which is substantially centrally located when said clutch plate is at rest, and which wedge element(s) slidably move radially outward in said at least one channel when said clutch plate is caused to rotate about said rod, wherein the operation is effected by the presence of magnetic material and/or a tensioning spring.        